Margesic

• Marnel Pharmaceuticals, Inc.

Margesic is part of the drug class:

• Anilides

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of acetaminophen, butalbital, and caffeine can be fatal.

The first signs of an acetaminophen overdose include loss of appetite, nausea, vomiting, stomach pain, sweating, and confusion or weakness. Later symptoms may include pain in your upper stomach, dark urine, and yellowing of your skin or the whites of your eyes.

Overdose symptoms may also include insomnia, restlessness, tremor, diarrhea, increased shallow breathing, uneven heartbeats, seizure (convulsions), or fainting.

In the U.S.

• Anolor 300
• Cephadyn
• Dolgic LQ
• Esgic
• Esgic-Plus
• Ezol
• Fioricet
• Geone
• Margesic
• Orbivan CF
• Phrenilin
• Phrenilin Forte

Available Dosage Forms:

• Tablet
• Capsule
• Solution

Butalbital, acetaminophen and caffeine are supplied in capsule form for oral administration.

Each capsule contains:

Butalbital ................... 50 mg

Warning: May be habit-forming.

Acetaminophen ........ 325 mg

Caffeine ...................... 40 mg

In addition, each capsule contains the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, magnesium stearate. microcrystalline cellulose with capsule shell composed of gelatin (silicon dioxide and sodium lauryl sulfate are added as manufacturing aides) and titanium dioxide. Imprinting ink composed of n-butyl alcohol, pharmaceutical glaze modified in SD-45, propylene glycol, SDA-3A alcohol, titanium dioxide, D&C Yellow No. 10 Aluminum Lake and FD&C Blue No. 1 Aluminum Lake.

Butalbital (5-allyl-5-isobutylbarbituric acid), a slightly bitter, white, odorless, crystalline powder, is a short to intermediate-acting barbiturate. It has the following structural formula:

C11H16N2O3  MW = 224.26

Acetaminophen (4'-hydroxyacetanilide), a slightly bitter, white, odorless, crystalline powder, is a non-opiate, non-salicylate analgesic and antipyretic. It has the following structural formula:

C8H9NO2 MW = 151.16

Caffeine (1,3,7-trimethylxanthine), a bitter, white powder or white-glistening needles, is a central nervous system stimulant. It has the following structural formula:

C8H10N4O2 MW = 194.19

This combination drug product is intended as a treatment for tension headache.

It consists of a fixed combination of butalbital, acetaminophen and caffeine. The role each component plays in the relief of the complex of symptoms known as tension headache is not completely understood.

Pharmacokinetics

The behavior of the individual components is described below.

Butalbital: Butalbital is well absorbed from the gastrointestinal tract and is expected to distribute to most tissues in the body. Barbiturates in general may appear in breast milk and readily cross the placental barrier. They are bound to plasma and tissue proteins to a varying degree and binding increases directly as a function of lipid solubility.

Elimination of butalbital is primarily via the kidney (59% to 88% of the dose) as unchanged drug or metabolites. The plasma half-life is about 35 hours. Urinary excretion products include parent drug (about 3.6% of the dose), 5-isobutyl-5-(2,3-dihydroxypropyl) barbituric acid (about 24% of the dose), 5-allyl-5(3-hydroxy-2-methyl-1-propyl) barbituric acid (about 4.8% of the dose), products with the barbituric acid ring hydrolyzed with excretion of urea (about 14% of the dose), as well as unidentified materials. Of the material excreted in the urine, 32% is conjugated.

The in vitro plasma protein binding of butalbital is 45% over the concentration range of 0.5 to 20 mcg/mL. This falls within the range of plasma protein binding (20% to 45%) reported with other barbiturates such as phenobarbital, pentobarbital, and secobarbital sodium. The plasma-to-blood concentration ratio was almost unity, indicating that there is no preferential distribution of butalbital into either plasma or blood cells (See OVERDOSAGE for toxicity information.)

Acetaminophen: Acetaminophen is rapidly absorbed from the gastrointestinal tract and is distributed throughout most body tissues. The plasma half-life is 1.25 to 3 hours, but may be increased by liver damage and following overdosage. Elimination of acetaminophen is principally by liver metabolism (conjugation) and subsequent renal excretion of metabolites. Approximately 85% of an oral dose appears in the urine within 24 hours of administration, most as the glucuronide conjugate, with small amounts of other conjugates and unchanged drug. (See OVERDOSAGE for toxicity information.)

Caffeine: Like most xanthines, caffeine is rapidly absorbed and distributed in all body tissues and fluids, including the CNS, fetal tissues, and breast milk.

Caffeine is cleared through metabolism and excretion in the urine. The plasma half-life is about 3 hours. Hepatic biotransformation prior to excretion, results in about equal amounts of 1-methylxanthine and 1-methyluric acid. Of the 70% of the dose that is recovered in the urine, only 3% is unchanged drug. (See OVERDOSAGE for toxicity information.)

Butalbital is habit-forming and potentially abusable. Consequently, the extended use of this product is not recommended.

Hepatotoxicity

Acetaminophen has been associated with cases of acute liver failure, at times resulting in liver transplant and death. Most of the cases of liver injury are associated with the use of acetaminophen at doses that exceed 4000 milligrams per day, and often involve more than one acetaminophen-containing product. The excessive intake of acetaminophen may be intentional to cause self-harm or unintentional as patients attempt to obtain more pain relief or unknowingly take other acetaminophen-containing products.

The risk of acute liver failure is higher in individuals with underlying liver disease and in individuals who ingest alcohol while taking acetaminophen.

Instruct patients to look for acetaminophen or APAP on package labels and not to use more than one product that contains acetaminophen. Instruct patients to seek medical attention immediately upon ingestion of more than 4000 milligrams of acetaminophen per day, even if they feel well.

Serious Skin Reactions

Rarely, acetaminophen may cause serious skin reactions such as acute generalized exanthematous pustulosis (AGEP), Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal. Patients should be informed about the signs of serious skin reactions, and use of the drug should be discontinued at the first appearance of skin rash or any other sign of hypersensitivity.

Hypersensitivity/anaphylaxis

There have been post-marketing reports of hypersensitivity and anaphylaxis associated with use of acetaminophen. Clinical signs included swelling of the face, mouth, and throat, respiratory distress, urticaria, rash, pruritus, and vomiting. There were infrequent reports of life-threatening anaphylaxis requiring emergency medical attention. Instruct patients to discontinue Margesic Capsules immediately and seek medical care if they experience these symptoms. Do not prescribe Margesic Capsules for patients with acetaminophen allergy.

General

Margesic Capsules should be prescribed with caution in certain special-risk patients, such as the elderly or debilitated, and those with severe impairment of renal or hepatic function, or acute abdominal conditions.

Information for Patients/Caregivers

This product may impair mental and/or physical abilities required for the performance of potentially hazardous tasks such as driving a car or operating machinery. Such tasks should be avoided while taking this product.

Alcohol and other CNS depressants may produce an additive CNS depression, when taken with this combination product, and should be avoided.

Butalbital may be habit-forming. Patients should take the drug only for as long as it is prescribed, in the amounts prescribed, and no more frequently than prescribed.

Laboratory Tests

In patients with severe hepatic or renal disease, effects of therapy should be monitored with serial liver and/or renal function tests.

Drug Interactions

The CNS effects of butalbital may be enhanced by monoamine oxidase (MAO) inhibitors.

Butalbital, acetaminophen and caffeine may enhance the effects of: other narcotic analgesics, alcohol, general anesthetics, tranquilizers such as chlordiazepoxide, sedative-hypnotics, or other CNS depressants, causing increased CNS depression.

Drug/Laboratory Test Interactions

Acetaminophen may produce false-positive test results for urinary 5-hydroxyindoleacetic acid.

Carcinogenesis, Mutagenesis, Impairment of Fertility

No adequate studies have been conducted in animals to determine whether acetaminophen or butalbital have a potential for carcinogenesis, mutagenesis or impairment of fertility.

Pregnancy 

Pregnancy Category C

Animal reproduction studies have not been conducted with this combination product. It is also not known whether butalbital, acetaminophen and caffeine can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. This product should be given to a pregnant woman only when clearly needed.

Withdrawal seizures were reported in a two-day-old male infant whose mother had taken a butalbital-containing drug during the last two months of pregnancy. Butalbital was found in the infant’s serum. The infant was given phenobarbital 5 mg/kg, which was tapered without further seizure or other withdrawal symptoms.

Nursing Mothers

Caffeine, barbiturates and acetaminophen are excreted in breast milk in small amounts, but the significance of their effects on nursing infants is not known. Because of potential for serious adverse reactions in nursing infants from butalbital, acetaminophen and caffeine, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness in pediatric patients below the age of 12 have not been established.

Geriatric Use

Clinical studies of butalbital, acetaminophen and caffeine capsules did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Butalbital is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.

Applies to acetaminophen / butalbital / caffeine: oral capsule, oral solution, oral tablet

Along with its needed effects, acetaminophen / butalbital / caffeine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking acetaminophen / butalbital / caffeine:

• Lightheadedness
• shortness of breath

• Abdominal or stomach pain
• black, tarry stools
• bleeding gums
• blistering, peeling, or loosening of the skin
• blood in the urine or stools
• blurred vision
• change in the frequency of urination or amount of urine
• chills
• cough
• diarrhea
• difficulty with breathing
• difficulty with swallowing
• dizziness
• drowsiness
• dry mouth
• fainting
• fast, pounding, or irregular heartbeat or pulse
• flushed or dry skin
• fruit-like breath odor
• hives, itching, or skin rash
• increased hunger
• increased thirst
• increased urination
• joint or muscle pain
• loss of appetite
• nausea or vomiting
• pinpoint red spots on the skin
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• red skin lesions, often with a purple center
• red, irritated eyes
• seizures
• shakiness in the legs, arms, hands, or feet
• sore throat
• sores, ulcers, or white spots in the mouth or on the lips
• sweating
• swelling of the feet or lower legs
• tightness in the chest
• trembling or shaking of the hands or feet
• troubled breathing
• unexplained weight loss
• unusual bleeding or bruising
• unusual tiredness or weakness
• weakness

Get emergency help immediately if any of the following symptoms of overdose occur while taking acetaminophen / butalbital / caffeine:

• Confusion as to time, place, or person
• dark urine
• difficult or painful urination
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• fever
• general feeling of discomfort or illness
• hallucinations
• headache
• holding false beliefs that cannot be changed by fact
• increased sweating
• irregular, fast or slow, or shallow breathing
• light-colored stools
• loss of appetite
• pale or blue lips, fingernails, or skin
• restlessness
• sudden decrease in the amount of urine
• sweating
• trouble sleeping
• unpleasant breath odor
• unusual excitement, nervousness, or restlessness
• vomiting of blood
• yellow eyes or skin

Some side effects of acetaminophen / butalbital / caffeine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

• Relaxed and calm
• sleepiness

• Anxiety
• bloated
• constipation
• continuing ringing or buzzing or other unexplained noise in the ears
• depression
• earache
• excess air or gas in the stomach or intestines
• false or unusual sense of well-being
• full feeling
• hearing loss
• heartburn
• heavy eyelids
• high energy
• hot spells
• hyperventilation
• irritability
• numbness
• pain in the leg
• passing gas
• sluggishness
• stuffy nose
• tingling sensation